coxph.wtest {survival} | R Documentation |

## Compute a quadratic form

### Description

This function is used internally by several survival routines. It computes a simple quadratic form, while properly dealing with missings.

### Usage

```
coxph.wtest(var, b, toler.chol = 1e-09)
```

### Arguments

`var` |
variance matrix |

`b` |
vector |

`toler.chol` |
tolerance for the internal cholesky decomposition |

### Details

Compute b' V-inverse b. Equivalent to sum(b * solve(V,b)), except for the case of redundant covariates in the original model, which lead to NA values in V and b.

### Value

a real number

### Author(s)

Terry Therneau

[Package

*survival*version 3.7-0 Index]